1. Field of the Invention
The present invention relates to communication in a wireless communication system and, more particularly, to an apparatus and method for controlling a communication path between a plurality of Digital Units (DUs) and a plurality of Radio Frequency Units (RFUs) in a wireless communication system.
2. Discussion of the Related Art
In a wireless communication system, in order to reduce installation costs for a base station and secure easy management, lots of Remote Radio Head (RRH) attempts have been made to couple DUs and RFUs using a wired line, such as an optical cable, and placing only RFUs in remote places. The RFU may also be called a Radio Unit (RU). Researches are recently being carried out on an effective wired connection between DUs and RFUs while active research is carried out on Cloud Communication Center (CCC) technology for integrating the DUs of a plurality of base stations into the communication station buildings of a network service provider.
FIG. 1 is a diagram showing a connection using a Passive Optical Network (PON) network between DUs and RFUs.
In technology shown in FIG. 1, attempts are made to solve the problem using the PON network having a master and slave architecture. In this technology, an Optical Line Terminal (OLT) 110 transmits the transmission signals of the DUs 100 of a plurality of base stations to an Optical Network Units (ONU) 160 or an Optical Network Terminal (ONT) in a frequency overlay form over the PON network by using an optical combiner 120. The ONU 160 or the ONT separates the signals, received from the DUs 100, by using an optical diplexer 140 and a Frame Multiplex Control Assembly (FMCA) 150, converts the separated signals into RF signals, and transmits the converted signal to a terminal through an antenna.
FIG. 2 is a diagram showing a connection using an Ethernet line between a DU and an RF module.
Technology shown in FIG. 2 relates to a method of transmitting signals from a DU 212 in a frequency overlay form through an Ethernet line 205 by using a control unit 220, separating the signals of the DU 212 by using an Ethernet AP w/MUX 230, converting the signals into RF signals by using an RF module 240, and transmitting the converted signals to terminals 252 and 254 through antennas 238 and 244.
The above technologies suggest only the methods of coupling one DU and an RFU limited to the DU in pairs, but does not propose a method of freely coupling a specific DU and specific RFUs or coupling a specific DU and specific antennas mounted on specific RFUs.